Substituted imidazolones and process of making them



Patented May 18, i948 ounce PATENT OFFICE "sussfrrrn rso nhhAzoLonnssmn PROCESS "OF MAKING THEM RobertDuschinsk'LiEssex Fells, N. i 12a Hofirnann-La :Roohe, Inc.,'Nu'fl*;*N. ifiafioiirporation of New Jersey No Drawing. ';ipp1ication@;uiy $113935, serial N 0. 6075915 claims. (classe -3 cc) 1 2. My invention rel'a't'esto the Synthesis of iimid- With a 'sajioh'ifyiii'g "'bi gfit, as will be shown in azolone compounds of the general formula "(*A) (A) d Y arehydrogen may be A romances hereinafter ens- R- :q-o 0-11 closed to replape hehy rog e'n atoms 'in the 1 wherein X and Y represent hydrogen, aIkyLsubaiid"3"pb'sitions y other-organ c radicals, therestituted alkyl, acyi, or substituted acyl, Rrieprebnpro uoin ppg pgu gi whi nd Y p sents hydrogen, alkyl, or substituted alkyl, and. snt '6r F- e her he hr' m 'en, COR is a member'of the group consisting of 10 Th'schein ofre'fic'tion is 'rp d s or the t'g'ene'rai formula acyl and substituted acyl radicals. V' 'S' Members of the general class illustrated above r possess utility in the manufacture of substances Frieda-Crafts having physiological activity. For example, cer- E 8 mmgmc Ubhmflon tain members of this class are particularly use- 1i! 12-4 i1 ful in the preparation of desthiobi'otin andre- (I lated compounds disclosed and claimed in my copending application Serial No. 533,3 96, filed 00 l April 29, 1944, now U. s. Patent No. 2,397,250 or 1 which the instant application is a continuation- R i, 5 00 R 1 B ,5,. in-part. l 1 I An important object of the invention resides 11 I in the rovision of a novel and effective method i do 1 of producing the chemical compounds with which n 1 the present invention is concerned. 1 9 Yet another Object'of the invention is to prepare compounds useful as intermediates "in the f 1v synthesis of other organic compounds. 1

Other objects will become apparent in the'light l of the following description of my invention. II 1 optional f The novel imidazolones of the general :rorin'ul'a l R-=c-c one (A), in which X and Y are hydrogen, may I derived, in general, from imid'azoion'es which are V represented y general formula (3) According-to thisseheme of reaction it will be 00 (J3) apparentthatcompound is converted into compound II by the Friedel-Orafts condensation. Compoundil -whiohhas hydrogen in the 1;3 po- =CH sitions; may-then be converted optionally into wher in R has the above significance, by means three classes of compounds: (7 A of a Friedel-Crafts condensation with a com- 40 .mawhgrei mzganig ub tituent replae the pound having the general formula I hydrogen in'the 1 and/or 3 position. I 7

' I IV-wherein theggoups'R and/or R in the-LI HEIOgGFiLRl compound are altered; withoutreplacing the hydrogen atoms in the 1 and/or-3position. I g wherein v -wherein one or more of the hydrogen atoms in the 1,3 positions, and one. or more of R, R are c- -n replaced;

The introduction of a side chain in the 5-position by a Frieda-Grafts condensation to form Compounds (B) may be prepared, ior examnie, g li is ff t g It i r a is sign can a n a repor e inves ga onon by heat ng imldflZOlgl'gB estersof the formula I membcrafts pa d fi iq th hefiemcycgc compounds, E. Ochiai, J; aharmy soc, Japan, {50,

EN NH lfi tim nbstract 1p; -(19Q0); C. A., 34-,

' Rnna oo my} u 5450 (io't'flhthestatcnient appears that 4-methy1- is a member selected from the group consisting of acyl and substituted acyi radicals.

3 imidazole and 2-phenyl-4-methyl-imidazole failed to react with acyl halides.

Specific examples of compounds which are embraced by my invention are:

v keto butyric acid (43) 4-methyl-5-imidazolcne- (2) keto pelargonic acid ethyl ester.

(44) 4-methyl-5-imidazolone- (2) -e -ket0 (no 6) bromo-caproic acid ethyl ester.

;(45) 1,3-diacetyl-4-methyl-5-imidazolone-(2) keto-(u or 6)bromo-caproic acid ethyl ester.

(46) 4-ethyl-5-imidazolone- (2.) e -ketocaproic acid ethyl ester.

(4'7) 4,4-thiodimethylene ibis -in1idazolone- (10) 1,3-diacetyl-4-thiouronium-methyl-5-imidazolone-(2) -e-keto-caproic acid ethyl ester bromide. I

(11) 4-isopropyl-5-imidazolone-2-'y-keto-butyric acid.

(12) 1,3-(p-toluenesulfonyl) -4 methyl 5 imid- .azolone-(2) -e-keto-'caproic acid methyl ester.

(13) 1,3-dipropi0nyl-4-allyl-5 imidazolone (2) e-keto-caproic acid methyl ester.

(14) 4-methy1-5-imidazolone (2) 'y methyl 6- keto-valeric acid.

(15) 1,3-diacetyl-4 benzyloxymethyl 5 imidazolone- (2) -e-keto-caproie acid methyl ester.

(16) 4-methyl- 5 -w hydroxy caproyl imidazclone-2.

(1'7) 4-methyl-5-imidazo1one- (2) -e-ketocaproic acid.

(18) 41- diethoxymethyl-5 imidazolonei- (2 6- keto-caproic acid. (19) 4-methyl-5-cyano-acetyl-imidazolone-2. (20) 1,4-dimethyl-5-imidazol0ne (2) e keto caproic acid. V (21) 1,3,4 trimethyl 5 -'imidazolone- (2) -e-k8l70- caproic acid.

(22) 1,3-dibenzyl-4-methyl-5 -imidazolone(2- sketo-caproic acid.

(23) 1,3-diacetyl-4 -benzyloxymethyl 5 -imidazclone-(2) -e-keto-caproic acid.

(24) 4-methyl 5 (A -heptenoyl) imidazolone-2.

(25) 4-methyl-5-cinnamoyl-imidazolone-2.

(26) 4-methyl-5-nicotinoyl-imidazolone-2.

(27) 4 methyl 5 (p nitrobenzoyl) imidaz clone-2.

(28) 4 methyl 5 (p aminobenzoyl) imidazclone-2. r

(29) 5,5-adipyl-bis- [4-methyl-imidazolone-2l.

(30') 4-ethylxanthogenyl methyl-5-imidazolone- (2) -e-keto-caproic acid ethyl ester.

(31) 4-methyl- 5 (p-benzamido -benzoyl) imidazolone-Z.

(32) 1,3-diacetyl-4-methyl-imidazolone- 2.'

(33) 4-methyl-5-imidazolone-(2) -e-k8t0- caproic acid ethyl ester. r V

(34) 1,3-diacetyl-4-methyl-5 -imidazolone- (2) e keto-caproic acid ethyl esten I (35) '4 methyl 5-acetyl-imidazolone-2; 7

(36) 4-methyl-5-imidazolone- (2') -'y-keto-butyric acid methyl ester.

(37) 1,3 diacetyl -4 -methyl- 5 acetyl --imidazclone-2. a i (38) 4-methyl-5-imidazolone- (2) -v-keto-butyric acid. (39) 5-imidazolone-(2) -e-keto'-caproi'c acid.

(40) 1,3-diacetyl -4 methyl 5 benzoyl -imidaz-' clone-(2). y 7 a V (41) ii-methyl- 5 methylaminoacetyl imidaz clone-(2) hydrochloride- 1 1 r I (42) 1 'or 3-monobenzoyl-4-methyl-S-imidazolone (2)-'y-keto'-caproic acidethyl ester.

(2) -e-keto-caproic acid]. (48) 4-methyl-5-imidazolone-(2) -glyoxylic acid. (49) 4- hydroxymethyl 5- imidazolcne (2) eketo-caproic acid. 7 (50) 1,3 diacetyl 4 acetoxyrnethyl 5 imidazclone-(2) -e-keto-caproic acid ethyl ester. ('51) 1,3- diacetyl-4 -bromoethyl 5 -imidazolone (2) -e-keto-caproic acid ethyl ester.

It will, of course, be understood that while the compounds listed above are individual, pure compounds, it is contemplated that such may, if desired, be prepared and effectively employed in the form of impure reaction mixtures. It will also be appreciated that mixtures of two or more of said compounds, in the pure or impure state, can also be utilized.

As pointed out above, compounds of the general formula (B) such as 4-methyl-imidazolone-2, may be prepared by treating the corresponding carboxylic acid alkyl ester with a saponifying 7 agent. A typical example of such a procedure is given as follows:

EXAMPLE A 4-methyZ-imidazolone-2 34 grams 4-methyl-5-imidazo1one-(2) -carboxylic acid ethyl ester Were dissolved in 215 cc. of 0.93 N sodium hydroxide (1 mol) and the solution kept68 hours at 5()-55. After cooling it was neutralized to pH '7 by gradual addition of 37.5 cc. of 5 N hydrochloric acid, which was accompanied by much carbon dioxide evolution and crystallization of the reaction product. The mixturejwas stirred in an ice bath for 1 hour, the methyl-imidazolone filtered off and Washed chlorine-free with some ice cold Water. After drying in an oven at 60, a first crop of 6.6 g. was obtained. M. P. 184-192 C.

. The mother-liquor was concentrated in vacuo, While the pH, which had the tendency to increase, was adjusted to 7 by gradual addition of 7 cc. N hydrochloric acid, and was finally brought to dryness. The white residue was extracted 3 times with 35 cc. of' boiling absolute ethanol, and once with ethanol. The alcoholic extracts, after separation from the undissolved sodium chloride, were concentrated to dryness, thus yielding a second crop of 8.55 g. methyl-imidazolone melting at ca. 178 C.

The total yield was 15.15 g. The crude material was directly used for the next step.

Sometimes the first crop of reaction product did not crystallize directly, but only after partial concentration of the solution in vacuo.

To.obtain a pure sample, the substance was twice recrystallized from 2 volumes boiling Water. M. P. 2025-2045 C. (after softening at 0.). For the analysis it was sublimed at 1 mm. (200 C. bath).

The substance is soluble in water, methanol, ethanol, acetone, also in hot dioxane, ethylacetate and nitrobenzene; insoluble in benzene, chloroform, ether and petroleum ether.

The aqueous or alcoholic solution reduces am moniacal silver nitrate and gives with ferric chloride solution a deep purple coloration.

EXAMPLE 1 4- r2gethyl-5-imidazolone-(2)w lceto-caproic acid ethyl ester 5.46 g. 4-methyl-imidazolone-2 (Example A) were suspended in 50 cc. nitrobenzene. 11.1 g. (1.04 mol) .of adipic acid mono-ethyl ester chloride were added, and the mixture stirred well in a three-neck flask fitted with an airtight mechanical stirrer and ascending condenser. With cooling in an ice bath, 15g. (2 mols) anhydrous aluminum chloride were added, vi' hich readily went into solution, accompanied by heat evolution. Then, with continuous stirring, the temperature wasraised to 60.-65 C. and maintained there for five hours. At that time, the evolution of hydrochioric acid had completely stopped.

The reaction mixture was a brown, viscous liquid. It was treated with 550 g. crushed ice and 100 cc. ether, whereupon yellowish crystals separated which were washed chlorine and nitroben- Zane-free with water and ether. After drying at 100? in vacuo, 7.67 g. of thereaction product were obtained. The yield was 54.0% of the theoretical. M. P. 170 C. *By recrystallization in 75 cc. of 50% ethanol, with addition of activated carbon, 6.73 g. (47.5%) of crystals, M. P. 171.5-173 C., were obtained. 3

The substance is soluble in alcohol and acetic acid, insoluble in water and ether. It gives only a very slight orange coloration with ferric chloride.

The, free acid is obtained from this ester by refluxing with a slight excess of normal sodium hydroxide and acidifying with hydrochloric acid. White crystals melting from -2-10-21 2 Cfiwere obtained.

' EX MPLE II 4-methyl-S-acetyl-imtddzolone-Z 1.96 g. 4-methyl-imidazolone-2 (Ex. A) was reacted with 1.35 g. acetylbrornide (1 mol) and 5.4 g. aluminum chloride (2mol) in 20 cc. nitrobenzene. The temperatureof the reaction was 60, and the time of reaction 5 hours. The reacnon-mixture was treated with ca. 50 g, ice, the

nitrobenzene was eliminated .by steam distillation, and the residual'solution (75 cc.) was decolorized by boiling with charcoal.

On cooling, 1.39 g. (49.5% of the theory) crystals separated. M. P. ,29329.6 (deal. The crude material was recrystallized from 70 cc. water; The 'yield was 0.9 g.; M. P.'321' (dec.). Forth'e analysis, 150 mg. were recrystallized a second time from cc. water, and 130mg. slightly yellowish crystals, melting at 322 (dec.), were obtained.

The substance is soluble in hot water and ethanol, strong acids, andalkali. It is almost insoluble in cold water and organic solvents. The alcoholic solution gives with'ferriochloride a yellow coloration. 'Refiuxing with'2 N sodium hydroxide for one hour did not affect the substance. Refluxing two hours with 20% hydrochloricacid :gave a 70% recovery, butsince the mother-liquor gave a-strong red ferric chloride was filtered' washed with wate.

. '6 reaction, some cleavage must have taken place. The substance gave an oxime decomposing. at about 297 C.

7 EXAMPLE III 5 -imz'dia-zolone- (2) -@-7cetocaproic acid ethyl ester A suspension of 1.68 g. crude imidazolone-Z in 20 cc. nitrobenzene was reacted with 3.84 w-carbethoxy valeryl chloride and 3 g. aluminum chloride at 60-64 for 4 /2 hours. The reaction mixture, when treated with 50 g. icejand 10D cc. ether, gave a pasty precipitate, which was purl,- fied'by dissolving in 20 cc. hot dioxane and precipitating with 60 cc. ether. The yield was 1.22 g. (25% of crude 5-imidazolone- (2) -e-keto-c aproic acid ethyl .ester, which after recrystallization melted at 218.

EXAMPLE IV 5-imiclae'ol0ne-(2) -e-ketocaproic acid 800 mg. of the ester of Example 111 were converted into the acid by heating Editor 45 minutes with 12 cc'. 0.5 N sodium hydroxide and reacidifying with 6 cc. N hydrochloric acid. The yield was 465 mg; M. P. 225. Afer recrystab lization from 25 volumes of water the product melted at 229.

ExaMPLE V 4-methyZ-5-imidazolone- (2) rd-kQtil-PQZdTgOOLiG acid ethyl ester acetic acid; insoluble in water, etherand acetone.

EXAMPLE VI 4-ethyZ-5-imidaeolone- (2) -e-lceto-caproi'c acid ethyl ester i A mixture of 1.62 g. 4-ethylimidazolone-2,20 cc. nitrobenzene, 2.77 g. w-carbethoxy-valeryl chloride, and 5.75 g. aluminum chloride was reacted 4 hours. at ("HP-". The reaction mixture, when poured on 20 2. ice and 55 cc. ether, deposited crystals which were Washed with water and ether. The yield was 1.32 g; M. P. i0'5'-107, and after recrystallization from 28 on. 15% alco hol 108109. The esteris very soluble in ethanol anddioxane; insoluble in water and ether.

'. f ExA PLs VII 'm il -5 -imidazolime-(2) -y-keto-but acid methyl ester 4.9 g. 4-methyl-imidazo1one-2 and 8.3 g. succinic acid mono-methyl ester chloride were suspended in 50 cc. nitrobenzene and reacted with 133g; aluminum chloride at hours and 5 minutes, he 1 evolution stopped. bro. was treated with'5i) ice an upon crystallization occurred 20 cc. alcohoL' The yield was 97 i i 7 Recrystallization from a mixture of 125 cc. water and 15 cc. ethanol in the presence of activated carbon yielded 2.49 g., melting at 211.5- 213.5.

A second recrystallization raised the melting point to 214.5-215.5.

EXAMPLE VIII 4-methyl-5-imz'dazolone- (2) -glyomylic acid 9.8 g. 4-methyl-imidazolone-2 and 14.65 g. ethyl-oxalo chloride were reacted in '75 cc. nitrobenzene with 26.6 g. aluminum chloride. Immediate violent gas evolution took place. After 3 hours, ca. 85% of the theoretical amount of hydrochloric acid has been evolved. The almost solid brown reaction mixture was treated with 100 cc. ether and 100 g. ice. Crystallization occurred and the resulting crystals were filtered and washed with water and ether. The yield was 4.04 g. of greenish-yellow crystals, melting at 240250 (dec.).

The crude product was recrystallized from 180 cc. of a mixture of equal volumes of alcohol and water with activated carbon, yielding 2.04 g. of a product decomposing at ca. 245.

A further recrystallization from 50% alcohol gave yellow crystals decomposing around 260.

This product is the free acid.

EXAMPLE IX 4-methyl-5-chloro-acetyZ-imidazolone-2 4- methyl-5-benzoyl-imidazolone-2 9.8 g. 4-methyl-imidazolone-2 and g. benzoylchloride were reacted in 75 cc. nitrobenzene with 26.6 aluminum chloride. The temperature was maintained at 6065 for 5 hours. The reaction mixture was then treated with 100 cc. ether and 100 g. ice. Pinkish-brown crystals were obtained, which were washed with 50 cc. water and 50 cc. ether.

The crude product was recrystallized from 320 cc. boiling 50% ethanol, giving 13 g. of white, fluffy crystals melting at 255.5258.

EXAMPLE XI Diacetyl-4-methyl-5-imidazolone-(2) -e-k26t0- caproic acid ethyl ester 3.75 g. of keto ester obtained in Example I were refluxed minutes with 15 cc. acetic anhydride. The solution was concentrated in vacuo, the residue again refluxed with 15cc. acetic anhydride and reconcentrated. The residue was then taken up in cold ethanol, whereupon crystals separated which were filtered ofi and washed with ethanol. The yield was 4.03 g.; M. P. 68-70. The substance was recrystallized from ethanol and sublimed at 0.7 mm. and 160 bath temperature. White crystals were obtained EXAMPLE XII Crime of 4-methyl-5-zmz'dazolone- (2) -e-ketocaproic acid To a solution of 113mg. of 4-methyl-5-im1dazolone-(Z)-e-keto-caproic acid in 2 cc. 0.5 N sodium hydroxide was added a solution of 69.5 mg. hydroxylamine hydrochloride in 1 cc. water. The mixture, having a pH of 6, was concentrated to dryness on a water bath. The residue was taken up with some water and acidified with 2 drops of hydrochloric acid, in order to bring the pH to 5.7. The separated crystals were washed with water and then with alcohol. The yield was 60 mg. g

The oxime was recrystallized from 10 cc. water with the addition of some alcohol. M. P. 224- 226 (dec.).

The oxime is insoluble in water and alcohol, and soluble in alkali. It can be reprecipitated from the alkaline solution by acid.

EXAMPLE X131 Crime of 4-m ethyl.5-acetyl-imidazolone-Z To a solution of mg. of 4-methyl-5-acetylimidazolone-2 in 10 .cc. of boiling water, were added 140 mg. of hydroxylamine hydrochloride and 272 mg. of sodium acetate, and the mixture was refluxed for one hour. Crystals separated during the heating. They were filtered off after cooling the reaction mixture, and were washed chlorine-free. The yield was 100 mg. M. P. 297 (dec.). From the concentrated motherliquor, another 50 mg. were recovered.

EXAMPLE XIV Diacetyl-4-methyl-5-imidazolone-(2) -s-k6t0- caproic acid ethyl ester A solution of 50.8 g. 4-methyl-5-imidazolone- (2)-E-keto-caproic acid ethyl ester in 200 cc. acetic anhydride was refluxed for 20 minutes. Most of the anhydride was then distilled off at atmospheric pressure. The residue was again refluxed with acetic anhydride, the solution was evaporated at atmospheric pressure and finally in vacuo. The solution of the brownish residual oil in 100 cc, ethanol deposited upon cooling the crystallized diacetyl derivative, which was filtered off and washed with cold ethanol. The yield was The alcoholic motherliquor gave, upon concentration and refluxing the residue again with 25 cc. of acetic anhydride, a second crop of the diacetyl-keto-ester, which was distilled at 0.6 mm. and 165 (bath temperature). It weighed 1.5 g.

"EXAMPLE XV Diacetyl-4-bromomethyl-5-imidazolone (2) -e Iceto-czrprozc acid ethyl ester A solution of 165 cc. of carbon tetrachloride. of 50.7 g. diacetyl-4-methyl-5-imidazolone-(2).- e-keto-caproic acid ethyl ester, was refluxed with 26.5 g. N-bromosuccinimide; until a sample of the mixture applied on moistened iodine starch paper gave no iodine coloration. As a rule the reaction was completedafter 40 to 60 minutes. The cooled solution, filtered from'the succinimide, gave upon evaporation in 'vacuo a crystalline mass, which was melted by warming on a water bath and poured into cc. ether. Matted needles separated'which were washed with about 100 cc. ether. The yield was 56 g. M. P'. 75 76.5". The product is quite soluble in benzene, dioxane,

7 F 9. ethyl acetate, and acetic acid; less in ether and alcohol; insoluble in petroleum ether. 11; can be recrystallized from alcohol.

EXAMPLE XVI sition, so that only 550 mg. of distillate were ob} tained; Colorless oil; n =1A92i EXAMPLE I 4-cthoscymcthyl-5-imidnzolone42)Herein; 9

caproic acid and its ethyl ester These two compounds can be obtained boil: ing the diacetyl-bromo ester pie XV in a ueous alcohol.

bromide atom by an ethoxy'group. Tlne reaction mixture is treated with silver acetateto remove the bromine ions present. The'mixture is then filtered, and the filtrate is cooled, depositing a mixture "or i-ethoxymeth'yl-5-imidazolone-(2) e-keto-caproic acid and its ethyl ester. This mix.- ture was treated with acetone, which has a greater solubility for the ester, and the free acid, thus obtained, was recrystallized from aqueous alcohol. It melted in an evacuated capillary at 214-217. It gives a red ferric chloride reaction.

The acetone soluble fraction gave, upon concentration, waxy crystals. These were recrystallized from ether and alcohol, and finally sublimed at 0.4 mm. and 1902ii0 (batch). The product thus obtained is the ethyl ester of l-ethoxymethyl-5-imidazolone-(2) -e-l;eto caproic acid, melting at 100-101.

EXAMPLE XVIII Diacetyl-4-aicetorymethyl-5-imidazolone- (2) e-keto-caprozc acid ethyl ester To a solution or 4.42 g. of diacetyl-bromomethyl keto ester described in Example XV, in 50 cc. glacial acetic acid, were added 1.77 g. silver acetate, with stirring and heating to 55, until the solution contained neither silver nor bromine ions. After separation from the silver bromide, the solution was evaporated and the almost colorless residue dried in vacuo at 100. The yield was 3.5 to 3.8 g. rif 1.4507.

EXAMPLE XIX 4,4-thi-dimethyZcne-bis- [-imidaeolone- (2) -e-lceto-capr0ic acid] stirring, at 50 C. for

i so

. described in Exam The boiling serves. to remove theacetyl groups and toexchan'g'e the" 1b was recrystallized from} coo volumes-of water. it melted at 252f -25f3 (tied) It was; easily soluble in alkali,-'alsb -1n pyridi ne'gimt hardly-soluble in' other Solvents: v

ExAMrLE-XX -mcthyZ-S-imidqeolob (2) -e-l'ceto-caproic acid A solution oi: 12 2 ling/of the foregoing sulfur compound, Ex.': ,K-.'X,in 5.5 cc. 0.1 N sodium hydroxide was shaken for 1 hour in a hydrogen atmosphere in the presence of 1 g. prehydrogem ated Raney nickel catalyst. The colorless filtrate gave upon acidification with hydrochloric acid of crystals melting at 213.5'-2l5.

i; 4-methyl-5-benzoyL-imidazolone-2 9.8 g. of d-methyl-imidazolone-Z and 14.05 g. of benzoyl chloride, were dissolvedin '75 cc. of distilled nitrobenz 'enej. To thestirred and cooled solutidr'iwere 'ad" 'ed'inthree portions 52.1'g, of anhydrous stannic chloride. The temperature'of the reaction-mixture'- was then gradually raised to between 60 and 65 C. Hydrogen chloride was evolved. After 3% hours the above reaction mixture was poured on g. crushed ice. Then 100 cc. of ether were added; and the mixture kept overnight at- 93G A precipitate formed, which was filtered I in i and was washed. on the filter with" water iandii eth'en benzoyl-imidazolone' z thusiis'olat'ed was recrystallized from aqueousl'alcoholj 'The yield Was 8.63 g. of the pure compound. M. P. 255257 C.

t will be appreciated that the proportions of reactants, times or" reaction, temperatures of reaction, and the like, may be varied and that supplementary processes, such as purification and the like, may be resorted to wherever found desirab-le or convenient. These and other variations and modifications will be evident to those skilled in the art in the light of the guiding principles disclosed herein.

Wherever the formula nucleus or the term imidazolone is employed in theclaims, it will be understood to cover the tautomeric forms,

What I claim is:

1. Compounds of the general formula 00 HN/ \NH 11%):33-00-3 where R is a member of the group consisting of hydrogen and aliphatic radicals, and CO-R.

is an acyl radical.

3. Compounds of the general formula The crude 4-methyl-5- EN \NH OHx-=l'J-UOR wherein CO-R. is an acyl radical.

5. Compounds of the general formula wherein CO-R is a carbalkoxy acyl radical.

6. Compounds of the general formula wherein Ac is acyl, and 00-4?) is a carbalkoxy acyl radical.

7. Compounds of the general formula 12 8-. Compounds of the general 1 Acetyl-N N iaa1 aoo-R formula wherein R is a member of the group consisting of hydrogen and aliphatic radicals, and CO-- 1=t is an acyl radical. V a

9. 4-methyl-5-imidazolonee(2) --k8t0 caproic acid ethyl ester.

10. Diacetyl 4 methyl 5 imidazolone (2) e-keto-caproic acid ethyl ester,

11. Diacetyl 4 acetoxy methyl 5 imidazolone- (2) -e-k8tO-O8P1Oi0 acidethyl ester.

12. A process which comprises reacting a member of the group consisting of imidazolone-2 and a 4-alkyl-imidazolone-2 compound with a carboxylic acyl halide in the presence of a Friedei- Crafts catalyst to form the corresponding 5-acylimidazolone-2 compound.

13. The process of claim 12 in which the 5-acylimidazolone-2 compound .is acylated to form a 1,3-diacyl-5-acyl-imidazolone-2.

14. The process of claim 12 in which a 4-alkylimidazolone-2 compound is employed to yield a corresponding 4-alkyl-5-acyl-imidazolone-2 compound.

15. The process of claim 12 in which the 5-acy1- imidazolone-2 compound is acetylated to form a 1,3-diacetyl-5-acyl-imidazolone-Z.

ROBERT DUSCHIN SKY. 

